1. Field of the Invention
The present invention relates generally to methods for forming optical fiber preforms, and particularly to methods for forming cladding portions of optical fiber preform assemblies by axially pressing silica glass soot around a glass core cane.
2. Technical Background
The cladding portion of an optical fiber preform may be formed from an outside vapor deposition (OVD) process in which silica glass is deposited on a glass core cane, for example, through the pyrolysis of octamethyltetrasiloxane. The OVD process is a highly optimized, high yield manufacturing process. However, the formation of the cladding layer is often the rate limiting step in maximizing optical fiber output. Further, it is estimated that as little as 50% of the pyrolysis product of the octamethyltetrasiloxane feedstock is deposited on the glass core canes during deposition of the cladding portion of the optical fiber preform. The remaining pyrolysis product of the octamethyltetrasiloxane feedstock is collected in a baghouse as relatively high purity silica glass soot.
In order to further improve optical fiber output and reduce raw material costs, alternative methods of faulting the cladding portions of optical fiber preforms are needed.